1. Field of the Invention
Screening for cervical cancer in women using cytological techniques has been possible for more than 40 years. The papanicolau test (pap test) has allowed for a significant reduction in mortality in women from cervical cancer. Prior to the pap test, cervical cancer was the most common cause of cancer deaths in women. In countries where pap smears are available, mortality from cervical cancer is negligible.
2. Description of the Related Art
In spite of this progress, there are several problems with the present technology. Conventional pap tests show a high percentage of smears of undetermined significance that requires further testing. This problem has led to the development of xe2x80x9cthin prepxe2x80x9d technology. Thin prep technology requires that cells be immersed in fixative and centrifuged prior to analysis. Other advances in diagnostic technology are the discovery of DNA probes for human papilloma virus (HPV), the causative agent of cervical cancer, and for chlamydia, a common infection in women. Tests for HPV may soon replace conventional pap smears as the initial screening test for cervical cancer. Collection of cytologic specimens currently requires a speculum examination which is frequently uncomfortable and embarrassing for women. It is also relatively expensive, since it requires the services of a physician or nurse practitioner. Finally, the specimen obtained is applied directly to a glass slide, which is not compatible with automated cytologic analysis or necessary for HPV assay. The same problems of discomfort, embarrassment, expense and processing also apply to the obtaining of specimens to diagnose vaginal infections such as candidiasis, gonorrhea, human papilloma virus and chlamydia.
Prior self sampling devices (described in the next section) were either designed prior to the invention of thin prep and HPV assay technologies or designed specifically to obtain a specimen in the setting of a conventional speculum examination. Given these problems, there is a need for an improved, inexpensive self sampling device which asymptomatic women can use in the privacy of their home that is adaptable to automated cytology methods (thin smear), HPV assay and microbial culture. This application discloses just such an improvement.
Several previously disclosed self sampling devices have failed because they fail to protect the sample from vaginal secretions and contamination (ex. U.S. Pat. Nos. 2,847,000; 3,776,219; 3,857,384). Below are described previously disclosed devices that are designed to protect the sample from vaginal contamination:
U.S. Pat. No. 5,121,752 discloses a self sampling device that utilizes a relatively large diameter hollow cylindrical speculum coupled with a mirror-guided hinged spatula. This device is not applicable for mass screening, since it is uncomfortable for many women to insert, and technically difficult for most women to manipulate in order to obtain an adequate specimen (to do this at home, it would require the manipulation of the speculum, the spatula, a mirror and a light source).
U.S. Pat. No. 3,995,618 discloses a double barreled plastic tube with a sponge on one end for self-sampling of cervical tissues. This device has some beneficial features including its simplicity of use and ability to protect the specimen from vaginal contamination. However, its plastic construction increases its expense and it is unnecessarily complicated, with an unwinding sponge which is dragged across an internal slide to: obtain the specimen. It is also not biodegradable and is more difficult to utilize than that of this disclosure. The device is therefore not designed to be inserted into a conical tube after the specimen is obtained, with the handle serving as the screw-cap seal - a feature which will allow the present proposed device to adapt to thin smear cytologic technique and microbiologic culture and HPV assay. It should be noted that thin smear cytology, automated cytology and microbiologic assays such as polymerase chain reaction or PCR tests did not exist when U.S. Pat. No. 3,995,618 was disclosed.
U.S. Pat. No. 2,847,000 is the prototype cervical self sampling device (filing date, Jul. 2, 1997). This device is designed to obtain cervical cytology specimens through a tampon-like device and then transfer the specimen to a slide enclosed within the tampon. This device never was put to clinical use. Its design is flawed because the cervical cells will adhere to the anterior portion of the sponge in a position that will not be transferable to the slide. This device is not compatible with thin prep technology.
U.S. Pat. No. 5,830,154 discloses a cylindrical tube with a slide attached to a screw cap allowing it to be immersed in fixative. It is not a self sampling device, although it could be modified slightly to be the receptacle of specimens obtained by this invention.
U.S. Pat. No. 4,945,921 discloses a vaginal self-sampling device designed exclusively to test vaginal pH. It cannot be used for cytologic or microbiological assay.
U.S. Pat. No. 4,952,204 discloses a swab with a handle enclosed in a sheath to protect the swab from contamination. The device was not designed for cervical self-sampling, nor is such an intent claimedxe2x80x94the purpose of the device is simply to maintain the sterility of the swab.
U.S. Pat. No. 5,339,828 discloses a device for obtaining specimens by trained clinicians through endoscopy. It is not practical or compatible with cervical self sampling.
U.S. Pat. No. 5,445,164, Worth et al. described an alternative approach to cervical self sampling, and is rather elaborate in design. Although this design seeks to address many of the issues and problems of self sampling, it is designed to be mailed in after use, as opposed to being immediately immersed in a fixative or preservative. This, at a minimum creates extra steps in handling and may interfere with the technique, sensitive and specificity of thin prep cytology. Again, it should be noted that this device was invented prior to the FDA approval of thin prep cytology (1996).
U.S. Pat. No. 3,857,384 is a cervical self sampling device in which specimens are sampled directly onto a smear. It is thus not compatible with thin prep cytology.
U.S. Pat. No. 4,164,212 discloses a device for obtaining mucus to determine menstrual phase. This is a device designed to evaluate problems with fertility, not cervical cancer or vaginal infections.
Accordingly, the present invention comprises a tampon-like device that will allow for the self sampling of cervical specimens. As such, the cervical sampling device comprises a tampon-like tube preferably made of a medical grade cardboard material, wherein the cardboard tube is structured to move or be selectively telescoped between an extended orientation and a compressed orientation. An extrudable and retractable sponge is housed within the cardboard tube and is sized for entry into the vaginal cavity so as to painlessly obtain cervical specimens utilizing a self-sampling procedure. Also, a handle is attached to the sponge and may form a screw cap of the type which is structured to be secured to a standard tube in which a fixative is contained such that the obtained sample is adequately preserved. The extended orientation of the tube serves to position the sponge on the interior thereof and the aforementioned compressed orientation selectively disposes the sponge or collection element outwardly from the tube to facilitate collection of the cervical specimen. The device will be inexpensive to produce, easy to destroy after use, and easy for women to use. It will allow for the safe transportation of the specimens to laboratories for analysis and is easily adaptable for centrifugation and thin-film preparation, or DNA probe for HPV, which is a technological improvement over the older direct preparation for a smear.
In a more limited application of this device, it can also be used to obtain specimens for culture or microbiologic assay. This will make it useful in the diagnosis of vaginal infections and for epidemiologic studies of sexually transmitted diseases.
These and other objects, features and advantages of the present invention will become more clear when the drawings as well as the detailed description are taken into consideration.